Update sort button to show sort direction icon

ee/app/assets/stylesheets/pages/roadmap.scss

@@ -34,14 +34,17 @@ $column-right-gradient: linear-gradient(
     }
 
     .dropdown-toggle-split {
-      color: $gl-text-color-secondary;
+      padding-top: $gl-btn-vert-padding;
       border: 1px solid $border-color;
       border-left: 0;
       border-top-right-radius: $border-radius-base;
       border-bottom-right-radius: $border-radius-base;
+      background-color: $white-light;
+      color: $gl-text-color-secondary;
 
       &:hover {
         color: $gl-text-color;
+        border-color: $gray-darkest;
       }
     }
   }

ee/app/helpers/ee/sorting_helper.rb

@@ -43,9 +43,12 @@ module EE
     # Creates a button with the opposite ordering for the current field in UI.
     def sort_order_button(sort)
       opposite_sorting_param = epics_ordering_options_hash[sort] || epics_ordering_options_hash.key(sort)
-      sort_icon = sort.end_with?('desc') ? 'sort-highest' : ' sort-lowest'
+      sort_icon = sort.end_with?('desc') ? 'sort-highest' : 'sort-lowest'
 
-      link_to sort_icon, page_filter_path(sort: opposite_sorting_param, label: true)
+      link_to sprite_icon(sort_icon, size: 16),
+              page_filter_path(sort: opposite_sorting_param, label: true),
+              class: "dropdown-toggle-split btn-sort-direction",
+              title: sort.end_with?('desc') ? _("Descending") : _("Ascending")
     end
 
     def sort_title_start_date

ee/app/views/shared/epic/_sort_dropdown.html.haml

@@ -11,7 +11,4 @@
         = sortable_item(sort_title_recently_updated, page_filter_path(sort: sort_value_recently_updated, label: true), sorted_by)
         = sortable_item(sort_title_start_date, page_filter_path(sort: sort_value_start_date_later, label: true), sorted_by)
         = sortable_item(sort_title_end_date, page_filter_path(sort: sort_value_end_date_later, label: true), sorted_by)
-    %button.dropdown-toggle-split.pt-2{ type: 'button' }
     = sort_order_button(@sort)
-      -#= sprite_icon('sort-highest', size: 16)
-      -#= sprite_icon('sort-lowest', size: 16)